The present invention is directed to a headspace gas sampling method and arrangements and filtering and sampling ports used therewith. More particularly, the present invention is directed to such method, arrangements and ports which are particularly suitable for sampling and filtering gases from waste material stored in containers, such as drums, wherein the material is a hazardous waste such as, but not limited to, transuranic waste.
Since 1970, transuranic waste material generated in the United States by the Department of Energy Operations has been packaged in unvented, 55-gallon steel drums, which drums have been stored with the intention of future retrieval. It is intended that the material in these drums will be disposed of permanently in the Department of Energy Waste Isolation Pilot Plant (WIIP) Facility. Currently, there are safety concerns regarding these stored drums because of the potential presence of combustible headspace gases. These gases can include hydrogen and methane, resulting from the radiolytic decomposition of hydrogenous waste materials, e.g. paper, plastics and moist materials and/or from the presence of small amounts of combustible volatile organic compounds (VOCs) that are co-contaminants of transuranic waste. Future transportation and storage of these wastes stored in drums such as 55-gallon drums must address what is to be done about these gases.
The WIPP facility has waste acceptance criteria that requires that all packages stored must be vented. Moreover, those packages which are to be shipped to the Waste Isolation Pilot Plant must be vented and demonstrated to meet combustible gas concentration limits before shipping.
In addition, it is necessary that these drums retain their integrity during shipment in case the drums are accidentally dropped or are involved in a road or railway accident during shipment. Since there are millions of these drums, it is assumed that there will be accidents or occurrences that may stress the drums and increase the risk of spills or leaks. It is therefore important that any sampling ports or filter ports not be dislodged so as compromise the integrity of the drums.
Moreover, since the drums must be sampled and filtered, it is desirable that the sampling and application of filters be performed in an expeditious and safe manner.
In view of the aforementioned considerations, the present invention is directed to a drum sampling and filtering arrangement wherein a sampling punch and a filtering punch are used for each drum, the sampling and filtering punches being inserted by remote control using a remotely activated drive.
In a more specific aspect, the remotely activated drive is a pneumatic gun which drives the filtering punch and then the sampling punch through the lid of the drum at spaced locations through the lid.
In a further aspect of the invention, a punch is configured for penetrating a wall to access a space behind the wall, wherein each punch comprises an annular body having first and second ends for passage therethrough, the passage having a first opening and a second opening. The punch point is coupled detachably the first end of annular body. The coupling releases the punch point upon inserting the punch point through the wall, whereby the first opening of the passage communicates with the space behind the wall. In accordance with a preferred arrangement, the coupling comprises a deformable element which releases the punch point upon the punch point being forced through the wall. In a more specific aspect of the invention, the coupling comprises a stud on the punch point which is received in the open end of the passage, the punch point being held in the passage by an element which releases the punch point after the punch point has penetrated the wall. In a still more particular aspect of the invention, the element which holds the stud of the punch point in the passage is a collar which disengages from the punch point as the punch point passes through the wall.
In accordance with one embodiment of the punch, the passage includes the septa seal therein adapted to permit the passage of a hollow needle therethrough to sample in the space behind the wall. In accordance with another embodiment of the punch, the passage has a filter element associated therewith, wherein any fluid which passes from the first opening in the body and through the second opening in the body must pass through the filter element.